Wednesday, March 27, 2024

Successful Case in Genetic Counseling for Premature Chromatid Separation (PCS) Syndrome

Source: https://www.cureus.com/articles/109045-genetic-counseling-for-an-infertile-couple-with-premature-chromatid-separation-pcs-syndrome-a-case-report#!/

Additional Recourses:

https://www.ncbi.nlm.nih.gov/gtr/conditions/C1864389/

https://www.plannedparenthood.org/learn/pregnancy/fertility-treatments

An article posted on Cereus.com documented the first successful case of genetic counseling for couples with Premature Chromatid Separation (PCS) Syndrome. PCS is a rare genetic syndrome found in only 40% of individuals. According to the National Library of Medicine, “Premature chromatid separation consists of separate and splayed chromatids with discernible centromeres and involves all or most chromosomes of a metaphase” (National Library of Medicine 2024). People that have this trait have no phenotypic symptoms, but there have been reports of decreased fertility for those who have it. People who seek genetic counseling can be provided with not only psychological support, but tests can also be run so information can be gathered to make a decision. 

The first successful test of couples who were treated for this syndrome occurred in August, 2016 on a wife that was 33 years old and had her third miscarriage at 10 weeks. They decided to run tests that showed an abnormal karyotype on the fetus, found to be 91, XXYY, -21, and was likely to be the cause of the miscarriage. Although the family tree indicated that the husband was a PCS carrier, a G-Band test confirmed that the husband was asymptomatic for PCS syndrome and PCS was not the cause of this couple's infertility. After further discussion, it was decided that the couple would continue infertility treatment as long as the husband stayed away from drugs such as  vincristine and vinblastine, and paclitaxel since carriers of PCS can be sensitive to them. In the end, the couple had a successful pregnancy in 2018. 

It is interesting to hear the great things that genetic counseling can do. In the beginning, this couple thought that they wouldn’t be able to have children as a result of PCS syndrome, but due to genetic counseling they were able to receive helpful information in order to make the decision to continue infertility treatment. I am excited to hear what else genetic counseling can do for people in the future! 





Secretoglobin SCGB1D2 found in human sweat may protect against those affected by Lyme's Disease

     Lyme's disease affects more than 500,000 people a year, the disease is carried by mice, deer, and other animals and is transmitted by ticks. The disease is caused by the bacterium Borrelia Burgdorferi, which can cause symptoms like fatigue, body aches, fever, and other symptoms that can usually be cleared up but, for others, these symptoms may linger for years. Michal Caspi Tal and Hanna Ollila, researchers at MIT, ran a genome-wide association study (GWAS) with included genome sequences for 410,000 people, 7,000 of them having Lyme's disease. The article described how the GWAS revealed how the secretoglobin, a family of proteins that play a role in immune responses to infection, SCGB1D2 (mainly produced by sweat glands) may be linked to the disease. Mice injected with borrelia burgdorferi exposed to a mutant version of the protein fell victim to the disease however, mice injected with borrelia burgdorferi exposed to the normal version of the protein showed no signs or symptoms of the disease. Though researchers are not sure how the protein inhibits bacterial growth, they found that the mutated version causes a shift from the amino acid proline to leucine. 

    I found the research that was done to be potentially life changing for many people. So many people suffer from Lyme's disease and is very common around woody areas, like the pinelands. The potential that has risen from these findings, as talked about in the article, could eventually be used to make protective creams, or new medicines for people whose symptoms are still around, even after antibiotics. The new information could also potentially be applied to dogs, another species commonly affected by the bacterium. I think it's amazing what could be found using huge genome databases. 



Article: A Protein found in human sweat may protect against Lyme disease

Reference: SCGB1D2 inhibits growth of Borrelia burgdorferi and affect susceptibility to Lyme disease

Potential Recovery of Dinosaur DNA!

 This article details an account which claims that $125 million-year-old DNA has been recovered from a dinosaur called Caudipteryx. Scientists claim that the fragments of chromatin and nuclei within the fossil could contain preserved DNA, which could then be extracted and studied. However, mass skepticism surrounds this idea. Currently, the oldest sequenced DNA belongs to a million year old woolly mammoth, and, given how long ago dinosaurs went extinct, the idea of sequencing multi-millions of years old DNA is nearly unheard of… This is due to DNA's fragility. The dinosaur DNA was allegedly extracted from fossilized femur cartilage, found in China. This fossil was exceptionally preserved, as the site it was found at is known for fossilization via fine volcanic ash- prime preservation conditions. However, the main concern surrounding this is the idea that the genetic material being found could actually be from microbes on the fossils, not the dinosaurs themselves. This is a problem that researchers commonly run into, not only with dinosaurs, but other ancient organisms as well.


Personally, I think that the concept of being able to study ancient DNA, and then further learn from it in the present day, is fantastical. However the obvious problems of being unable to differentiate between modern organisms and fossil DNA is a major setback. Additionally, due to DNA's tendency to break down over time, unfortunately, I am also a skeptic in regards to whether or not DNA was actually recovered from this dinosaur. However, if somehow we were able to develop a way to differentiate modern versus ancient DNA, I think it would be amazing to compare ancient DNA to modern DNA, and see just how similar dinosaur DNA is to that of modern organisms. 





Tuesday, March 26, 2024

Are Bengal Cats Less Exotic than They Seem?

Source https://med.stanford.edu/news/all-news/2024/03/bengal-cats.html

Reference https://www.purina.co.uk/find-a-pet/cat-breeds/bengal


Sarah C.P. Williams’ article posted on Stanford Medicine stated that researchers at Stanford Medicine studied the origins of Bengal cat’s coats and determined that it most likely stemmed from domesticated cats. These cats were assumed to be bred from the genes of an Asian leopard and a house cat. Many people want bengal cats because of their wild-like leopard appearance but domesticated personality. However, it has been reported that the appearance of Bengal cats have always been around in domesticated cats. 

Researcher Gregory Brash and his colleagues sequenced 947 Bengal cat genomes and found that there were no parts of the Asian leopard cat genomes that would have been assumed to be found in all Bengals. Instead, the results determined that the appearance of Bengals was a result of genetic variations that were already present in domestic cats. In the end, it was decided that the ideal Bengal Cat coat could have been achieved with the simple domestic cat genome. 

This research is very interesting. Not only does it determine that Bengal cats are not as exotic as originally thought, but it also highlights the fact that many people are paying, on average $1,500 – $3,000 on a cat that is not actually what it seems. I am curious to see if the prices of Bengal cats decrease as a result of this study. 




Genetically Modified Pigs Aiding in the Shortage of Organs for Transplants

Over 100,000 individuals remain on the waiting list for an organ transplants, and tragically, about 17 individuals perish daily due to the unavailability of suitable organs. In response to this critical shortage, scientists are diligently researching the feasibility of utilizing genetically modified pigs to address this pressing medical need.

Nestled discreetly near Blacksburg, Virginia, lies a secret farm comprising 22 meticulously maintained buildings housing roughly 300 pigs. These pigs serve as subjects for extensive research aimed at exploring their potential in human organ transplantation. Referred to as a "barrier facility," these buildings must maintain absolute sterility to shield the pigs from any potential pathogens. The journalist working on the article emphasized the rigorous sterilization process implemented before entering the pig-containing premises. 

The process of genetically modifying these pigs involved sophisticated technology to edit the DNA in their skin cells. Following editing, similar techniques that were used on Dolly the Sheep are utilized to generate cloned pig embryos. A tiny pipette is employed to penetrate the egg and extract DNA, removing the majority of genes. Subsequently, edited cells are fused with emptied eggs using electrical stimulation, initiating cell division and resulting in the formation of new embryos. These embryos are then surgically implanted into female pigs, and within a span of four months, cloned piglets are born. These piglets contain ten genetic modifications ensuring their suitability for organ transplantation and compatibility with recipients. 

However, amidst the potential medical breakthroughs, ethical concerns arise. Many question the morality behind modifying, breeding, and ultimately slaughtering these animals for human benefit. L. Syd Johnson, cited in the article, denounces the process as an act of "hubris," likening it to the treatment of animals as mere machinery. I agree with this statement; the entire process is deeply disconcerting. While modern medicine continues to extend human lifespans, we must pause and reflect on the ethical boundaries we are willing to transgress. Though this procedure holds promise in saving lives and mitigating transplant wait times, it compels us to confront the profound moral implications of our technological advancements.

Why Humans Don't Have Tails

In the article titled “A genetic parasite may explain why humans and other apes lack tails”, the author explains that a jumping gene or Alu element is a parasite that is possibly responsible for the evolution of apes and humans not having tails like monkeys do. The article shows that research was conducted on mice and when the TBXT protein, which is responsible for tail growth, was altered, mice would be born with a shortened tail or no tail at all. This supports the hypothesis that a parasite could be responsible for tail loss in apes and humans because the parasite would also result in an altered TBXT protein. 


This is a really interesting hypothesis about why humans are born without tails. At first, I did not think a parasite would be responsible for such a huge evolutionary change and thought this article would be fake or clickbait. After reading about the mice experiment in the article, I think this is a very likely theory and that a parasite could very well have caused this mutation 25 million years ago.








Beethoven's Report Card


This entertaining article discussed if the famous musical composer from the late 16th century, had genetic predisposition to be a gifted musician, and if we have the means to confidently make such a claim. This sounds like a drunken bet someone would make at a bar, but whoever said scientist can't get out and have a good time?
    It turns out Beethoven's genome was already sequenced in 2023 by researchers using a lock of his hair (I'd love to hear the story of how someone got their hands on his hair!). So these researchers working together from different international universities were able to analyze the sequence and run a polygenic test on 'beat synchronization'; basically testing if Beethoven could hold a rhythym (a 1 and a 2 and a). Unfortunately, Beethoven's scores were nothing to write to the queen about. 
   So what's the value in this? Well obviously Beethoven was and is and exceptional musician, so this actually points us to the reliability of the test. Polygenic tests are used when multiple genes are thought to influence a disease, trait, or behaivor. We compile data from a population for these tests, and then can use them to predict the likeyhood or intensity someone will have said disease, trait, behaivor. It's a lot to get into, but two important things to know: is music ability influenced by our genes: partially, Yes. Can we rely on a tests to say whether someone's unborn child will be musically gifted: No, that would ruin the suprise.

Posted by Michael Breslin
 
Source: https://news.vumc.org/2024/03/26/beethovens-genes-reveal-low-predisposition-for-beat-synchronization/#:~:text=Ludwig%20van%20Beethoven%2C%20one%20of,Aesthetics%20in%20Frankfurt%20am%20Main%2C